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spi: add config option to enable the WP pin function on st micron flashes

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enable the W#/Vpp signal to disable writing to the status
register on ST MICRON flashes like the N25Q128 thorugh
the new config option CONFIG_SYS_SPI_ST_ENABLE_WP_PIN

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
This commit is contained in:
Heiko Schocher 2014-07-18 06:07:21 +02:00 committed by Stefano Babic
parent a0ae0091d7
commit 562f8df18d
3 changed files with 45 additions and 0 deletions
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11
README
View file

@ -2930,6 +2930,17 @@ CBFS (Coreboot Filesystem) support
memories can be connected with a given cs line.
currently Xilinx Zynq qspi support these type of connections.
CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
enable the W#/Vpp signal to disable writing to the status
register on ST MICRON flashes like the N25Q128.
The status register write enable/disable bit, combined with
the W#/VPP signal provides hardware data protection for the
device as follows: When the enable/disable bit is set to 1,
and the W#/VPP signal is driven LOW, the status register
nonvolatile bits become read-only and the WRITE STATUS REGISTER
operation will not execute. The only way to exit this
hardware-protected mode is to drive W#/VPP HIGH.
- SystemACE Support:
CONFIG_SYSTEMACE

4
drivers/mtd/spi/sf_internal.h
View file

@ -60,6 +60,10 @@
#define STATUS_QEB_MXIC (1 << 6)
#define STATUS_PEC (1 << 7)
#ifdef CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
#define STATUS_SRWD (1 << 7) /* SR write protect */
#endif
/* Flash timeout values */
#define SPI_FLASH_PROG_TIMEOUT (2 * CONFIG_SYS_HZ)
#define SPI_FLASH_PAGE_ERASE_TIMEOUT (5 * CONFIG_SYS_HZ)

30
drivers/mtd/spi/sf_probe.c
View file

@ -281,6 +281,34 @@ int spi_flash_decode_fdt(const void *blob, struct spi_flash *flash)
}
#endif /* CONFIG_OF_CONTROL */
#ifdef CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
/* enable the W#/Vpp signal to disable writing to the status register */
static int spi_enable_wp_pin(struct spi_flash *flash)
{
u8 status;
int ret;
ret = spi_flash_cmd_read_status(flash, &status);
if (ret < 0)
return ret;
ret = spi_flash_cmd_write_status(flash, STATUS_SRWD);
if (ret < 0)
return ret;
ret = spi_flash_cmd_write_disable(flash);
if (ret < 0)
return ret;
return 0;
}
#else
static int spi_enable_wp_pin(struct spi_flash *flash)
{
return 0;
}
#endif
static struct spi_flash *spi_flash_probe_slave(struct spi_slave *spi)
{
struct spi_flash *flash = NULL;
@ -351,6 +379,8 @@ static struct spi_flash *spi_flash_probe_slave(struct spi_slave *spi)
puts(" Full access #define CONFIG_SPI_FLASH_BAR\n");
}
#endif
if (spi_enable_wp_pin(flash))
puts("Enable WP pin failed\n");
/* Release spi bus */
spi_release_bus(spi);